648 



NA TURE 



[October 24, 1907 



sphere, thus confirming the results previously obtained by 

 Sir Norman Lockyer, Profs. Hale and Adams, and others. 

 There are strong reasons for believing that the spectrum- 

 producing vapours of Mira were at a higher temperature 

 during the 1906 than during the 1897 maximum. In the 

 first place the star was brighter, and therefore presumably 

 hotter. Again, the changed intensity of the hydrogen lines 

 and of the characteristic absorption bands also indicates, 

 according to our present knowledge, an increased tempera- 

 ture in 1906. Concurrently, the titanium-o.\ide bands in 

 the spectrum of Mira were weaker in iqo6 than in 1897, 

 and, as these bands are stronger in the spot spectrum 

 than in that of the photosphere, it seems reasonable to 

 conclude that the spot vapours are therefore cooler than 

 those of the general photosphere. 



The evidence thus afforded by the temperature, and the 

 accompanying spectral, changes of Mira from one maxi- 

 mum to a higher one agrees with Sir Norman Lockyer's 

 temperature classification of the stars wherein similar 

 changes, from type to type, are held to determine the 

 relative positions of the Antarian and Aldebarian groups. 



Recently discovered Minor Pl.vnets. — In No. 4205 

 (October 10) of the Astronomische Nachrichten, Prof. 

 Bauschinger gives a list of thirty-four recently discovered 

 minor planets showing the permanent designatory number 

 that has been allotted to each. The last date of discoverv 

 given is June 9, 1907, and up to that time six hundred and 

 thirty-five of these objects had been allotted permanent 

 numbers. The present list also gives the provisional desig- 

 nation, the name of the discoverer, the date of discovery, 

 and, where it has been allotted, the proper name by which 

 each asteroid is to be known. A second list gives the 

 elements for the orbit of each minor planet where they 

 have been determined. Fifteen of these objects, which 

 were allotted provisional numbers in 1906-7, have been 

 found to be identical with previous discoveries. 



Elements of Comets 1907a and igo7i. — .'\ set of para- 

 bolic elements for the orbit of comet 19070 is published 

 by Signor E. Tringali in No. 4205 of the Astronomische 

 h'achrichten (October 10). 



The same journal also contains a set of parabolic 

 elements for comet 19071?, calculated by Prof. E. 

 Millosevich from observations made on June 16, Julv 18, 

 and August 22. The results of a number of observations 

 of the latter comet made at the Kremsmiinster Observatory 

 during the period July 4 to August 28 are given by Prof. 

 F. Schwab in the same issue. On August 18 the comet 

 was of 2c; magnitude, and its tail was seen to extend 16° 

 in the direction from \ to 7 Geminorum. 



The Liverpool Astronomic.\l Society. — We have re- 

 ceived the annual report of this very active society giving 

 a brief ri<sume of the work done and papers read during 

 the session 1906-7. .Among the latter, reference may be 

 made to the president's address delivered at the opening 

 meeting by Mr. W. E. Plummer, who, in a most interest- 

 ing paper, directed attention to a few of the more urgent 

 problems at present facing the practical and the theoretical 

 astronomer. 



An excellent photograph of Mr. George Higgs is re- 

 produced as a frontispiece, and that observer contributes 

 a short paper dealing with recent advances in the absolute 

 wave-length measurements of solar radiation. Some 

 curious phenomena were described by Mr. C. T. Whitmell, 

 who sunposed the observer to be located on the sun, and 

 from that standpoint surveyed the solar system. Of more 

 practical interest were the pacers by the Rev. R. Killip, on 

 the planet Jupiter ; Mr. H. Waters, who presented a few 

 notes to beginners in stellar photography ; and Mr. F. W. 

 Longbottom, on work with a i2:5-inch reflecting telescope 

 of 24-inrh focus. The two last-named papers are illus- 

 trated by reproductions of photographs, that of the vicinity 

 of 7 Cassiopei.-E having been taken bv Mr. Waters with a 

 :^^-inrb Voigtlander portrait lens of 8 inches focal length 

 mounted on a rough equatorial stand and driven by hand. 



A MonERN Sun-dial. — The August number of the Bulletin 

 de la Sor.iHi astronomique de France (p. 360) contains 

 an interestino- illustrated description of a sun-dial which 

 the author, Vicomte d'Aurelle Montmorin, thinks may suit 

 the modern requirements of the general public. The usual 

 NO. 1982, VOL. 76] 



gnomon is replaced by a wire stretched across a rect- 

 angular frame, its shadow being cast on to a semi- 

 circular dial at the back. The frame is adjustable on 

 pivots to any latitude, and curves engraved on the instru- 

 ment give the equation of time for every fifth day. 

 Setting screws are provided to adjust for longitude, once 

 for all, and for the equation of time, so that no calcula- 

 tion is necessary, the time being read off directly from the 

 dial, which is divided into divisions of five minutes each. 

 The instrument is very portable, and the author suggests 

 an ingenious arrangement of selenium cells whereby the 

 hours and quarters might be struck on one or two gongs. 



FLEAS AND PLAGUE. 

 CIR LAUDER BRUNTON, K.R.S., delivered the 

 ■^ inaugural address at the opening of the twenty-fifth 

 session of the London School of Tropical Medicine on 

 Monday, October 25, Mr. R. L. Antrobus, C.B., .Assistant 

 Under Secretary of State for the Colonies, presiding. 

 He described the campaign against mosquitoes in relation 

 to malaria and yellow fever ; sleeping sickness, its spread 

 along the lines of commerce in .Africa and its transmission 

 by a tsetse-fly ; and then proceeded to discuss plague. The 

 ravages of this disease in Europe in the fourteenth century 

 under the name of the " Black Death " were described, 

 and quotations from contemporary writers were given 

 illustrating the terrible condition to which the countries 

 attacked were reduced by the pestilence. 



In India at the present moment the ravages of plague, 

 though not so groat as those of the Black Death or of 

 the Great Plague in London, are nevertheless dreadful. 

 During the first si.x months of this year no less than 

 1,060,000 deaths from plague occurred in India, and out 

 of these 632,000 occurred in the Punjaub, which has a 

 population of only twenty-five millions, that is to say, one 

 in every forty inhabitants in this district has died of plague 

 between January and June. 



It has long been observed that great mortality in rats is 

 apt to precede pestilence, and Mr. Hankin suggests that 

 the story of the Pied Piper of Hamelin is a legendary 

 .account of a plague epidemic. Simond first suggested that 

 fleas transmitted the virus, and the most convincing 

 experiments have been made by Captain W. Liston, 

 I. M.S., who found that 61 per cent, of white rats and 

 S2 per cent, of Bombay rats contracted plague from fleas 

 which had fed upon infected rats. He then found that 

 fleas would infect guinea-pigs. He further showed that 

 guinea-pigs did not catch plague if they were protected 

 from fleas in various ways, e.g. by wire gauze, adhesive 

 fly-paper, &c. His experiments have been confirmed and 

 extended bv the Advisory Committee appointed by the 

 Secretary of State for India, the Royal Society, and the 

 Lister Institute, who concluded from their experiments 

 that :— 



(i) Close contact with infected animals does not give 

 rise to plague epidemic among guinea-pigs when fleas are 

 excluded. 



(2) If fleas are present, epidemic starts at once. 



(3) .An epidemic may be started when no contact with 

 a plague-infected anim.al is allowed, when fleas from in- 

 fected animals are introduced. 



(4) Infection can take place without the animal being 

 in contact with the ground. Thus a guinea-pig put in 

 a wire cage and suspended 2 inches from the ground con- 

 tracted disease. 



(5) Aerial infection did not take place if the cage was 

 2 feet (that is. more than fleas jump) from the ground. 



(6) In all the animals thus naturally infected the large 

 proportion, 90 per cent, (nearly), of the buboes were in 

 the neck ; 179 animals were examined, and in obtaining 

 fleas from animals 653 per cent, were obtained from head 

 and neck. 



The great diflficulties in the way of preventive measures 

 are ignorance and apathy, to which superstition is often 

 superadded. In some parts of India there is £<reat pre- 

 judice against taking life of any kind, but this is not 

 universal, because in some parts goats are oR'ered to Kalee, 

 the Goddess of Destruction. If the Brahmins could per- 



